Method and apparatus for forming a multiple sectioned ring

ABSTRACT

Apparatus for forming a ring structure comprised of a multiple number of elements substantially forming the ring, which sections are utilized in cathode ray guns to provide the electrical circuit for energizing the cathode filaments of the electron gun. Four separate sections form the ring. The apparatus for forming the arrangement is to provide a single stamped member having the thickness of the order of 5 mils and mounting the member upon a jig to form a substantially circular shaped configuration. The member is then positioned in close proximity to the electron gun structure adjacent the elements to which it is being mechanically connected. The ring shaped member is then welded to the supporting structures and, after weldment, is positioned in a ring cutter assembly which cuts the substantially ring shaped member at three points located approximately 120* apart to thereby form four separate elements which are then utilized for electrical connection to filament leads of a plurality of cathode heaters mounted within the electron gun structure. This technique replaces the conventional technique in which six separate elements are utilized to form the filament ring.

United States Patent [191 Minutillo [451 July 17, 1973 METHOD AND APPARATUS FOR FORMING A MULTIPLE SECTIONED RING Leonard D. Minutillo, Parlin, NJ.

[73] Assignee: Griffiths Electronics, Inc., Linden,

[22] Filed: Dec. 23, 1970 [2]] App]. No.: 100,929

Related U.S. Application Data [62] Division of Ser. No, 822,961, May 8, 1969, Pat. No

[75] Inventor:

Primary Examiner-R. F. Staubly Attorney-Samuel Ostrolenk et al.

[57] ABSTRACT Apparatus for forming a ring structure comprised of a multiple number of elements substantially forming the ring, which sections are utilized in cathode ray guns to provide the electrical circuit for energizing the cathode filaments of the electron gunv Four separate sections form the ring. The apparatus for forming the arrangement is to provide a single stamped member having the thickness of the order of 5 mils and mounting the mem ber upon a jig to form a substantially circular shaped configuration. The member is then positioned in close proximity to the electron gun structure adjacent the elements to which it is being mechanically connected. The ring shaped member is then welded to the supporting structures and, after weldment, is positioned in a ring cutter assembly which cuts the substantially ring shaped member at three points located approximately 120 apart to thereby form four separate elements which are then utilized for electrical connection to filament leads of a plurality of cathode heaters mounted within the electron gun structure. This technique replaces the conventional technique in which six separate elements are utilized to form the filament ring.

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METHOD AND APPARATUS FOR FORMING A MULTIPLE SECTIONED RING This application is a divisional application of application Ser. No. 822,961 filed May 8, 1969, now U.S. Pat. No. 3,562,898, issued Feb. 16, 1971.

The present invention relates to electron tube fabrication and more particularly to a novel method and apparatus for fabricating cathode ray tube electron guns especially of the type employed in color TV tubes wherein the six separate elements heretofore utilized to form the filament ring are replaced by a single element which is then welded and cut at predetermined locations to form the filament ring.

In order to mass produce electron tubes of the type having a multiplicity of components it becomes necessary to both automate as many operations in electron tube fabrication as is possible, as well as striving to reduce the number of total operations required in the fabrication of electron tubes.

As one example, in the mass production of electron gun assemblies utilized in color TV receiver tubes, the number of components comprising the electron gun is large and hence the number of fabrication steps is quite large, necessitating automation and a reduction in the number of fabricating steps 'to the greatest practical extent.

Electron gun structures utilized in color TV receiver tubes of the shadow-mask type are each comprised of three separate electronguns arranged substantially at 120 intervals about a central axis in order to produce the three separate electron beams which are scanned across the tube shadow-mask to pass through the openings in the shadow-mask and to impinge upon the associated colors of the phosphor dot pattern and thereby reproduce the original color image. The filaments of the individual electron guns within the composite structure are connected in electrical circuit by means of a filament ring comprised of a number of separate components sufficient to electrically couple all of the filament leads as well as to provide two tabs for electrical connection to the filament power supply. Conventional methods for fabricating the filament ring consisted of providing the total number of individual segments, positioning these segments relative to the filament leads, welding the components-to associated supporting structures and then welding these elements to associated leads of the filaments. Components which serve to provide the filament power are typically arranged in a ringshaped fashion and are commonly referred to as collectively forming the filamentring structure. Due to the rather small size and fragile nature of these components, handling and welding becomes rather complex and tedious.

The present invention is characterized by providing novel apparatus for fabricating the filament ring structure in which only a single part is utilized to form the composite ring structure,-which single member is appropriatcly welded to the supporting structure and then I ment leads.

The present invention is comprised of a heater ring fixture for receiving and positioning, in arcuate form, a single stamped member. The fixture which is formed ofa metal having good conductive properties is placed in a welding fixture so as to operate as a first electrode of the welding apparatus. The remaining structure of the electron gun is lightly force-fitted to one end of the fixture so as to be aligned with the single stamped member. The welding unit includes a second welding electrode and means for positioning the second electrode relative to points between the stamped'member and the related supporting components of the electron gun structure and then producing each weld. Upon completion of the welding operation, the stamped member is simultaneously cut at predetermined intervals around its periphery to form the final filament heater ring which is then ready to be joined to the individual filaments. This method and apparatus thereby enables the filament heater ring to be fabricated rapidly and accurately through mass production techniques, wherein the operations are performed substantially automatically and the number of fabrication steps are substantially reduced.

It is therefore one object of the present invention to provide a novel method and apparatus for forming the heater ring assembly of electron gun structures in a rapid, reliable and substantially automatic fashion.

Another object of the present invention is to provide a novel fixture and ring cutter and machine for forming a heater ring assembly wherein the fixture is designed to hold a single stamping member, to operate as an electrode for the welding operation'and wherein the ring cutting machine simultaneously cuts the stamping into three separate components preparatory to establishing the electrical circuit path for the heater filament leads such that the above fabrication steps are performed rapidly and accurately as compared with the conventional techiques.

These as well as other objects of the present invention will become apparent when reading the accompanying description and drawings in which:

FIG. 1 is a plan view showing the stamped part utilized with the method and apparatus of the present invention.

FIGS. 2a and 2b are side and end views respectively of the heater ring fixture utilized for mounting .the stamping shown in FIG. 1.

FIGS. 3a and 3b are elevational and top views respectively, showing an electron gun structure fabricated in accordance withthe principles of the present invention.

FIG. 4 is a plan view showing a welding apparatus which may be utilized with the apparatus of the present invention.

FIGS. 5a and 5b are end views, respectively, showing the cutting apparatus of the present invention.

FIGS. 6a, 6b and 60 show further details of the apparatus of FIGS. 50 and 5b, wherein FIG. 6a is a sectional view taken along the lines A-A' of FIG. 6a and wherein FIG. 60 is a sectional view taken along the lines B-B' of FIG. 6a.

Referring now to the drawings, FIG. 1 shows a plan view of a stamping utilized with the method and apparatus of the present invention in which stamping I0 is a flat metallic member which may preferably be stain less steel, whose planar dimensions are preferably as shown in the figure and whose thickness is of the order of 0.005 inch. As can clearly be seen from this figure, the stamped member is a substantially flat thin metallic member and has a C-shape configuration comprised of a central portion 11 and upwardly projecting arms 12 and 13 which form tabs for connecting an electrical circuit thereto in a manner to be more fully described.

FIG. 3a shows an elevational view of a portion of an electron gun assembly and FIG. 3b shows the top view of the electron gun assembly of FIG. 3a which may be fabricated in accordance with the concepts of the present invention. The electron gun assembly is comprised of three separated electron gun portions 21-23 which are arranged at 120 intervals about a central axis designated by the point 24 in FIG. 3b. Since all of the electron gun structures are substantially identical to one another, only one of these structures will be described herein for purposes of simplicity. The electron gun 22 is comprised of a cathode member 25 welded within a supporting cylinder 26. The cathode is heated to a temperature sufficient to cause the cathode to emit electrons with the electron emission toward the face of the cathode ray tube being controlled by a control grid 27. The cathode 25 is heated by a filament positioned within the hollow interior 25a of cathode 25 and is a thin wire which heats the cathode to an elevated temperature level sufficient to cause the cathode to emit electrons. The filament is provided with a pair of leads 28 extending out of the opening 25a of the cathode, which leads are then electrically connected to a pair of conductive sections 29 and 30. The filament leads of electron gun 21 are similarly electrically connected to conductive members 29 and 31, while the filament leads of electron gun 23 are electrically connected to conductive members 30 and 32, respectively, to form a series circuit simultaneously energizing all of the filamerits of the three electron guns 21-23. The electrical circuit is established through a pair of tabs integrally formed with and extending upwardly from conductive pieces 31 and 32, which tabs are designated by the numerals 33 and 34, respectively.

The electron gun structure is further provided with three elongated insulating members 35-37 which mechanically support all components of the electron gun structure while electrically insulating all of the parts. These insulating members, such as, for example, member 35 are provided with a pair of metallic support members 38 and 39 whose first ends are imbedded into the insulating member 35 and whose free ends are bent outwardly to form welding surfaces for the support of conductive member 29. Insulating members 36 and 37 are likewise provided with supports for respectively welding conductive segments 30, and 31-32 thereto. It

can clearly be seen from a consideration of FIG. 3b that i the conductive members 29-32 form acircular or ringshaped configuration and hence are referred to as the cathode heater ring assembly.

Heretofore the separate segments 29-32 were individually cut to size, formed and then welded to the as sociated supports. The present invention provides a method and apparatus for forming the cathode heater ring assembly from a single stamped member of the type shown in FIG. I, which single member is then bent to form the circular configuration welded to the aforementioned supports and then cut at the gaps 40, 41 and 42 between the separate sections so as to automate the fabrication of the cathode heater ring assembly and to eliminate a number of fabrication steps and thereby simplify the manufacture of electron gun structures of the type shown in FIGS. 3a and 3b.

FIGS. 2a and 2b are top and side views, respectively, of a ring fixture I5 utilized to form and weld the flat stamped member 10 of FIG. 1 to the electron gun structure. The ring fixture 15 is formed of a conductive metallic material and is comprised of a first cylindrical shaped member 16 having a central opening 16a. A second circular shaped member 17 formed of a con ductive metallic material has its left-hand end (relative to FIG. 21 inserted into the right-hand end of opening 16a. These members are rigidly joined to one another by suitable fastening means (not shown) threadedly engaging tapped apertures l8a-l8c and having their forward ends bearing against the surface of member 17 to rigidly secure member 17 within member 16.

Metallic member 17 is provided with a circular shaped flange 17a having two slots 17b and 170.

The stamped member 10 (see also FIG. 1) is placed around the periphery of member 17 near its right-hand end so that the tabs 12 and 13 pass through slots 17b and and extend into a groove 16b formed between flange 17a and a continuous shoulder 16c formed in member 16. A closed loop garter spring (shown only in sectional fashion in FIG. 2b) is fitted around groove 16b so as to bear upon tabs 12 and 13 and maintain the stamped member 10 in the curved position about member 17 as shown best in FIG. 2b. This fixture is then placedupon a welding apparatus 50, shown in FIG. 4. The welding apparatus 50 is comprised of a motor 51 or any other suitable driving means for the purpose of rotating a shaft 52 mechanically coupled thereto. The opening 16a of fixture 15 is force lifted upon the end of shaft 52 in the manner shown in FIG. 4. The electron gun structure 20 (minus the cathode heater ring) is force fitted upon the right-hand end of fixture 15 so that its support members (see support members 38 and 39, for example, of FIG. 3b) embrace the stamped member 10 such that the support members make physical engagement with the stamped member at spaced intervals around its surface. A pin 19 fitted into an opening 17d in fixture member 17 further acts to centrally locate and orient the electron gun structure 20 relative to fixture 15. The pin is positioned in the open space between the electron gun structures and is substantially aligned with the longitudinal axis of the gun structure as represented by the point 24 of FIG. 3b. Pin 19 orients the location of the ring tabs with respect to each of the electron gun barrels, i.e., the red, green or blue gun.

The fixture 15 is electrically coupled by any suitable means to an energy source 53. The electrical coupling 1 may be by means ofa lead 54 which may be electrically connected either to fixture 15 or shaft 52. If desired, lead 54 may make sliding electrical connection with either shaft 52 or fixture 15. An insulating coupler 55 may electrically insulate motor source 51 from fixture 15 while mechanically coupling the output of motor 51 to the fixture. The fixture 15 serves as one electrode of the welding apparatus. The other electrode is coupled by lead 56 to a second electrode 57 positioned along one radius of the fixture and having its tip immediately adjacent the outer periphery of the electron gun sup port members (such as support members 38 and 39, for example).

The welding operation is performed in the following manner:

Motor means 51 is energized to rotate fixture 15 in order to position the points to be welded immediately beneath the tip of electrode 57. For example, considering FIG. 3b, the first weld may occur at point 58 for the purpose of joining support 39 to segment 29. Obviously, the starting point may occur anywhere around the periphery of the electron gun structure and point 58 is merely cited as being one exemplary starting point. Motor means 51 is deenergized to hold this position and energy source 53 is energized to provide a weld at point 58. Motor means 51 is then energized rotating fixture so as to locate point 59 (see FIG. 3b) immediately adjacent the tip of electrode 57. Motor means 51 is then deenergized and energy source 53 is energized to produce a weld at point 59. Before rotation of fixture l5, electrode 57 is.retracted by either mechanical or automatic means so as to move the electrode in the direction shown by arrow 60 to provide sufficient clearance for support member 36 upon rotation of fixture 15. Motor means 51 is then energized to place point 61 immediately beneath the tip of electrode 57. Electrode 57 is then moved either by mechanical or manual means in the direction shown by arrow 62 so as to have its tip immediately adjacent point 61. Energy source 53 is then energized to produce a weld at point 61. The fixture 15 is repeatedly rotated and electrode 57 is further retracted when necessary to provide welds at the points 63, 64 and 65 so as to weld the stamped member at spaced intervals around its surface to associated supports of the electron gun structure.

Upon completion of the welding operation, the electron gun structure may simply be removed from fixture 15 and placed in a cutting assembly to form the separate segments 29, 30, 31 and 32 by means of a cutting assembly shown in FIGS. 5a6c.

Cutting assembly 70 is comprised of a support or base member 71 which may be placed on any suitable support surface. A cutter base 72 is mounted upon the plate 71 by means of three stand offs 73a-73c whose bottom ends are secured by fastening means 75 (only one of which is shown in FIG. 5b for purposes'of simplicity), and whose top ends are secured to cutter base 72 by fastening means 76a-76c, respectively. Cutter base 72 is provided with a central opening 72a surrounded by an upwardly extending flange portion 72b integrally formed with space 72. A cylindrical shaped mandrel 73 ispositioned within opening 72a and has its lower end 73a(of slightly smaller diameter) force fitted into a cooperating opening 74a provided in mandrel locating block 75 secured to base 72 by fastening means 76. Mandrel 74 is provided with a circular groove 74b near its upper end and with three slots 740-742 arranged at 120 intervals about the top end of the mandrel.

A ring shaped member 77 is secured to base 72 and is provided with an opening 77a which surrounds and is spacedfrom flange 72b. Member 77 is provided with a flat circular shaped surface 77b for slidably supporting a cam ring 78 whichmay be rotated in opposing directions as shown by double headed arrow 79 by an opcrating mechanism to be more fully described.

The operating mechanism is comprised of an air cylinder apparatus 79 having a first end thereof secured to support member 71 by fastening means 80. While not shown in detail for purposes of simplicity, it should be understood that the air cylinder assembly 79 is provided with a hollow cylindrical shaped interior for reciprocally mounting and moving a piston member mechanically coupled to a connecting rod 81. The forward end of the connecting rod is provided with an eyelet 82 for receiving a fastening member 83 which threadedly engages a tapped aperture 78a provided in cam ring provided in cam ring 78. In operation air pressure is introduced into the cylinder (by means not shown) causing connecting rod 81 to move toward the right (relative to FIG. 5a) to rotate cam ring 78 in a counterclockwise direction relative to FIG. 5a. Removal of the air pressure and application of a vacuum or alternatively application of air pressure in the opposite surface of the piston serves to move connecting rod 81 toward the left relative to FIG. 5a causing the cam ring 78 to rotate in the clockwise direction relative to FIG. 5a.

Cam ring 78 is provided with three elongated cam slots 79a-79c arranged at substantially equally spaced intervals about the cam ring. Each of these slots receive a cam follower 82-84 respectively, which are arranged to slidably engage the peripheries of their associated slots. Since each of the cam followers are substantially identical in configuration and function, only one will be described herein for purposes of simplicity. Considering FIG. 6b, the cam follower 84 slidably engaging slot is comprised of a circular shaped roller member 83a mechanically coupled to a pin 83b extending into a suitable opening provided in member 77. Pin 83b is secured within the opening in member 77 by means of a set screw 85 fitted into a tapped aperture 770 was to secure pin 83b to member 77. Roller 83a is secured to pin 83b so as to prevent any linear motion between the two parts, thereby preventing roller 83 from lifting upwardly and away from pin 83b. However, roller 83a is free to rotate about pin 83b. Each of the blocks 77, 88

and 89 (see FIGS. 6a and 6c) is provided with a pair of shoulders such as for example, the shoulders 77d and 77e arranged to slide within an elongated slot 90a provided within a cover plate 90. Similar slots are provided for each of the members 88 and 89. Circular cover plate 90 may be secured to cutter base 72 in any suitable manner such as by elongated fastening means, for example, which may be positioned at spaced intervals between the slides 77, 88 and 89. The slide 77 is provided with a narrow elongated slot 77d fitted with a cutter member 91 shown best in FIG. 6b. Three such cutter members 91-93 are provided for each of the slides 77, 88 and 89, respectively. Each cover plate is fitted with a slide cover such as, for example, the cover 94 secured to the top of the slide 88 by fastening means 95. Slide 77, shown in FIG. 6a, has its slide cover re-.

moved and shows a portion of the cover plate 90 broken away to expose the shoulders 77d and 77ein the slide. However, the cover plate 96 and fastening means 97 are shown in FIG. 6a for slide 89. Each-of the cutters are provided with a sharp forward edge arranged to pass through associated slots' 74c, 74d and 74e provided in mandrel 74. In operation, the electron gun structure is placed uponthe mandrel 74 which is provided with two projections 98 and 99 that are arranged to fit in the openings 100 and 101 shown in FIG. 3b which are defined by the ring sections and the supports to which they are welded. This establishes orientation between the cutter blades and the electron gun structure. Initially, the connecting rod 81 is in its uppermost position (not shown) relative to FIG. 6a. Air pressure is introduced to move the connecting rod 81 vertically down ward relative to FIG. 6a to thereby move the 'cam ring 78 in the counterclockwise direction. The cam followers 82-84 move inward along respective radii of the cutter to form the gaps 40, 41 and 42, shown best in FIG. 3b. The air cylinder 79 is then operated to move the connecting rod 81 vertically upward relative to FIG. 6a causing the cam ring 78 to rotate in the clockwise direction and thereby remove the slides and their associated cutters outwardly along their respective radii. The electron gun structure may then be removed and transferred to the next location whereupon the heater filaments may be inserted within the cathode openings and these filament leads such as the filament leads 28 may then be welded or otherwise electrically connected to the associated ring section such as, for example, sections 29 and 30, to establish a series electrical circuit to connect a power supply through tabs 12 and 13 to each of the three filaments of the electron guns comprising the structure.

It can be seen from the foregoing description that the present invention provides an automated means for simply and rapidly forming a cathode heater ring assembly and electron gun structures in which the number of fabrication steps are significantly reduced as compared with conventional techniques through the use of a single stamped member which is formed in an arcuate manner upon a fixture positioned relative to the electron gun structure welded at a plurality of locations and then cut into a single cutting operation to form the cathode heater ring assembly.

Although there has been described a preferred embodiment of this novel invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appending claims.

What is claimed is:

1. Welding apparatus for welding a flat metallic member to a supporting structure having a plurality of support members to be joined to said flat member wherein said support members are arranged at spaced intervals about an imaginary circle, said apparatus comprising:

a fixture for receiving said flat member and said supporting structure, said fixture comprising a metallic conductive member having a circular configuration;

said fixture having a circular shaped flange adjacent one end thereof, said flange having a pair of slots arranged at spaced intervals therealong;

a circular shaped groove adjacent said flange and positioned on the side of said flange opposite said one end;

said flat metallic member having a C-shaped configuration;

a closed loop biasing member positioned within said groove and adapted to hold the arms of said C- shaped member which extend through said slot and into said groove when said flat conductive member is wrapped about said fixture adjacent said flange;

said support structure being positioned over said one end of said fixture with its support members engaging said flat conductive member;

a shaft;

means for rotating said shaft in an intermittent manner;

said fixture having an opening in the end thereof opposite said one end for mounting upon said shaft;

an energy source;

an electrode removably positionable adjacent the periphery of said one end of said fixture;

said energy source being electrically coupled between said fixture and said electrode to weld the support positioned adjacent said electrode when said energy source is activated and said electrode is brought into engagement with said support member;

said rotating means including means for rotating said fixture to index the next support member to be welded to said flat member beneath said electrode after completion of the previous welding operation.

2. The apparatus of claim 1 further comprising means for moving said electrode away from said fixture prior to rotation thereof to allow sufficient clearance be tween said electrode and said supporting structure during rotation of said fixture.

3. Welding apparatus for welding a flat C-shaped metallic member to a supporting structure having a plurality of support members to be joined to said flat member wherein said support members are arranged at spaced intervals about an imaginary circle;

a fixture for receiving said flat member and said supporting structure, said fixture comprising a cylindrically shaped metallic member for mounting said flat member;

said fixture having a flange positioned inwardly from one end thereof, said flange having a pair of slots arranged at spaced intervals along its periphery;

a circular shaped groove positioned adjacent said flange and on the side of said flange opposite said one end;

a closed loop spring member positioned within said groove and adapted to hold the arms of said C- shaped flat member against said fixture, which arms extend through said slots and into said groove when said member is wrapped about said fixture and adjacent said flange;

a shaft;

means for rotating said shaft in an intermittent manner;

said fixture having an opening in the end opposite said one end for coupling said shaft;

said supporting structure being a three-gun electron gun structure fitted upon said one end of said fixture with said support members engaging said flat metallic member at a plurality of locations along its periphery;

an energy source;

an electrode removably positionable adjacent the periphery of said one end of said fixture;

said energy source being electrically coupled between said fixture and said electrode to weld the support positioned adjacent said electrode when said energy source is activated; said rotating means including means for rotating said fixture to index the next support member to be welded to said flat member beneath said electrode after completion ofthe previous welding operation. 4. The welding apparatus of claim 3 wherein said electron gun structure is comprised of a plurality of insulating members mechanically supporting the components of the electron gun structure;

thin metallic support members each having a first end secured to its associated insulating member and having an outwardly bent free end positioned to en gage the surface of the Gshaped member wrapped about said fixture. 

1. Welding apparatus for welding a flat metallic member to a supporting structure having a plurality of support members to be joined to said flat member wherein said support members are arranged at spaced intervals about an imaginary circle, said apparatus comprising: a fixture for receiving said flat member and said supporting structure, said fixture comprising a metallic conductive member having a circular configuration; said fixture having a circular shaped flange adjacent one end thereof, said flange having a pair of slots arranged at spaced intervals therealong; a circular shaped groove adjacent said flange and positioned on the side of said flange opposite said one end; said flat metallic member having a C-shaped configuration; a closed loop biasing member positioned within said groove and adapted to hold the arms of said C-shaped member which extend through said slot and into said groove when said flat conductive member is wrapped about said fixture adjacent said flange; said support structure being positioned over said one end of said fixture with its support members engaging said flat conductive member; a shaft; means for rotating said shaft in an intermittent manner; said fixture having an opening in the end thereof opposite said one end for mounting upon said shaft; an energy source; an electrode removably positionable adjacent the periphery of said one end of said fixture; said energy source being electrically coupled between said fixture and said electrode to weld the support positioned adjacent said electrode when said energy source is activated and said electrode is brought into engagement with said support member; said rotating means including means for rotating said fixture to index the next support member to be welded to said flat member beneath said electrode after completion of the previous welding operation.
 2. The apparatus of claim 1 further comprising means for moving said electrode away from said fixture prior to rotation thereof to allow sufficient clearance between said electrode and said supporting structure during rotation of said fixture.
 3. Welding apparatus for welding a flat C-shaped metallic member to a supporting structure having a plurality of support members to be joined to said flat member wherein said support members are arranged at spaced intervals about an imaginary circle; a fixture for receiving said flat member and said supporting structure, said fixture comprising a cylindrically shaped metallic member for mounting said flat member; said fixture having a flange positioned inwardly from one end thereof, said flange having a pair of slots arranged at spaced intervals along its periphery; a circular shaped groove positioned adjacent said flange and on the side of said flange opposite said one end; a closed loop spring member positioned within said groove and adapted to hold the arms of said C-shaped flat member against said fixture, which arms extend through said slots and into said groove when said member is wrapped about said fixture and adjacent said flange; a shaft; means for rotating said shaft in an intermittent manner; said fixture having an opening in the end opposite said one end for coupling said shaft; said supporting structure being a three-gun electron gun structure fitted upon said one end of said fixture with said support members engaging said flat metallic member at a plurality of locations along its periphery; an energy source; an electrode removably positionable adjacent the periphery of said one end of said fixture; said energy source being electrically coupled between said fixture and said electrode to weld the support positioned adjacent said electrode when said energy source is activated; said rotating means including means for rotating said fixture to index the next support member to be welded to said flat member beneath said electrode after completion of the previous welding operation.
 4. The welding apparatus of claim 3 wherein said electron gun structure is comprised of a plurality of insulating members mechanically supporting the components of the electron gun structure; thin metallic support members each having a first end secured to its associated insulating member and having an outwardly bent free end positioned to engage the surface of the C-shaped member wrapped about said fixture. 